1. Field of the Invention
The present invention relates to a manufacturing apparatus and manufacturing method, and more particularly, to an apparatus and method for manufacturing a liquid crystal display (LCD).
2. Discussion of the Related Art
In response to an increasing demand for displays devices having different operational characteristics, various display devices have been developed including liquid crystal displays (LCD), plasma display panels (PDP), electro-luminescent displays (ELD), and vacuum fluorescent displays (VFD) to replace conventional cathode ray tube (CRT) devices. In particular, LCD devices are commonly used because of their high resolution, light weight, thin profile, and low power consumption. In addition, LCD devices are commonly implemented in mobile display devices, such as monitors for notebook computers, and display monitors for computers and televisions. Accordingly, efforts to improve image quality of LCD devices have directly conflicted with the benefits of their high resolution, light weight, thin profile, and low power consumption. Thus, to incorporate LCD devices as general image display devices, image quality must be maintained.
Methods for manufacturing an LCD device may be divided two different categories: liquid crystal injecting and liquid crystal dropping. The liquid crystal injecting method includes steps of forming a sealant pattern on a first substrate to form an injection inlet, bonding the first to a second substrates in a vacuum state, and injecting liquid crystal material through the injection inlet. The liquid crystal dropping method, which is disclosed in Japanese Patent Application Nos. 11-089612 and 11-172903, includes steps of dropping liquid crystal material on a first substrate, arranging a second substrate over the first substrate, and joining the first and second substrates, thereby bonding the first and second substrates in a vacuum state. Compared to the liquid crystal injection method, the liquid crystal dropping method is advantageous since various steps, such as forming the liquid crystal material injection inlet, injecting the liquid crystal material, and sealing of the injection inlet may be omitted.
FIG. 1A is a cross sectional view of a substrate bonding device during a loading process according to the related art. In FIG. 1A, the substrate bonding includes a frame 10, an upper stage 21, a lower stage 22, a sealant dispenser (not shown), a liquid crystal material dispenser 30, an upper chamber unit 31, a lower chamber unit 32, a chamber moving system, a receiving system, and a stage moving system.
The chamber moving system includes a driving motor 40 driven to selectively move the lower chamber unit 32 to a first location where deposition of the sealant and/or the liquid crystal material occur. The driving motor also is driven to move the lower chamber unit 32 to a second location where the bonding process is performed.
The stage moving system includes another driving motor 50 driven to selectively move the upper stage 21 in a vertical direction. The driving motor moves the upper stage 21 in a downward direction during a bonding process, and moves the upper stage 21 along an upward direction during a loading/unloading process.
The receiving system temporarily receives an upper substrate, which is attached to the upper substrate to the upper stage 21, at both diagonal portions of the upper substrate. The receiving system includes a rotational axis 61, a rotational actuator 63, an elevating actuator 64, and a receiving plate 62.
FIG. 1B is a cross sectional view of the substrate bonding device according to the related art during a bonding process. A process of manufacturing a liquid crystal display device using the substrate bonding device according to the related art will be described with regard to FIG. 1B. In FIG. 1B, a second substrate 52 is loaded and affixed onto the upper stage 21 by a vacuum chuck, and a first substrate 51 is loaded and affixed onto the lower stage 22 by a vacuum chuck. Then, the lower chamber unit 32 having the lower stage 22 is moved from a loading/unloading position to the first location by the chamber moving system 40 for sealant and/or liquid crystal material deposition. Next, the lower chamber unit 32 is moved from the first location to the second location by the chamber moving system 40 in preparation for bonding of the first and second substrates 51 and 52 by the chamber moving system 40 after the sealant and/or liquid crystal material have been deposited onto the first substrate 51 by the liquid crystal dropping dispenser. Thereafter, the upper and lower chamber units 31 and 32 are positioned by the chamber moving system 40 and joined together to form a closed processing chamber. Next, the elevating and rotational actuators 64 and 63 are driven so that the receiving plate 62 is positioned at two edges of the second substrate 52 affixed to the upper stage 21.
FIG. 2 is a perspective view of a receiving system according to the related art. In FIG. 2, the second substrate 52 is allowed to drop onto each of the receiving plates 62 of the receiving system by releasing of the vacuum chuck, and pressure at an interior of the processing chamber is reduced by a vacuum device 70 (in FIG. 1B). When a vacuum state is achieved inside the processing chamber, the second substrate 52 is affixed to the upper stage 21 by an electrostatic force applied to the upper stage 21, and the first substrate 51 is affixed to the lower stage 22 by an electrostatic force applied to the lower stage 22. In addition, the rotational and elevating actuators 63 and 64 (in FIG. 1B) of the receiving system are driven to prevent the receiving plate 62 and the rotational axis 61 from interfering with bonding of the first and second substrates 51 and 52. Finally, the upper stage 21 is moved downward by the stage moving system 50 (in FIG. 1B) while in the vacuum state to closely fasten the second substrate 52 to the first substrate 51.
However, the substrate assembly device according to the related art has the following limitations. Since the interior of the processing chamber is in the vacuum state during bonding of the first and second substrates 51 and 52, a temperature in the interior of the processing chamber abruptly drops and any ambient moisture within the processing chamber condenses upon surfaces within the processing chamber. For these reasons, the liquid crystal material and/or the sealant may peel way from the first substrate 51, resulting in a defective substrate assembly.